The present invention relates to a mold for forming molded concrete products, and, more particularly, to a unitary mold for forming molded concrete products.
There are several problems that occur with prior art machines for forming concrete products which have previously been disclosed and addressed in earlier filed applications. A novel method and apparatus for forming concrete products was designed for the high speed manufacturing of a wide variety of high quality products was disclosed in U.S. Pat. No. 5,395,228 to Aeseth et al., for Apparatus for Forming Concrete Products and is incorporated herein by reference. That invention increased vibration control in a concrete product forming machine, reduced the amount of time required to mold concrete products, increased the homogeneous consistency of concrete products, and reduced the amount of time required to exchange and align molds in a concrete product forming machine.
A novel self-aligning mold box assembly for use in a machine for forming concrete products, such as the machine disclosed in U.S. Pat. No. 5,395,228 to Aeseth et al., is disclosed in my U.S. Pat. No. 5,743,510, and which is directed to the mold box depicted in FIG. 1.
Another novel mold box assembly for use in a machine for forming concrete products, such as the machine disclosed in U.S. Pat. No. 5,395,228 to Aeseth et al., is disclosed in my U.S. Pat. No. 5,542,837 for Method and Apparatus for Securing Partition Plates in a Mold, and incorporated herein by reference.
While both the machine for forming concrete products disclosed in U.S. Pat. No. 5,395,228 to Aeseth et al. and the two new mold box assemblies disclosed in my U.S. Pat. No. 5,743,510 and my U.S. Pat. No. 5,542,837 have substantial advantages over the prior art, each involves the use of mold box assemblies which in and of themselves impose limitations on product throughput, and which require labor-intensive assembly prior to use.
Turning now to FIG. 1A, included therein is an exploded view of a prior art paver grid assembly 100, which includes a paver grid 110 and a paver grid frame 112. In operative condition, paver grid 100 is secured to and contained within frame 112. The upper surfaces of the paver grid and frame are substantially coplanar when the grid and frame are in operative condition.
Paver grid frame 112 includes a pair of opposed mounting brackets 114, 116. Each of the mounting brackets has a pair of upwardly directed mounting surfaces, like surfaces 118, 120 on bracket 114. Each mounting surface 118, 120 includes a pair of bolt holes therethrough. Mounting bracket 116 includes mounting surfaces and bolt holes that are substantially symmetrical with mounting surfaces 118, 120 and the bolt holes therein.
A head assembly 122 is, in operative condition, mounted on a machine for making concrete products like that shown in FIG. 1B. The head assembly includes plurality of compression shoes, like shoe 124, that are aligned with corresponding cavities in paver grid 110, also mounted on the machine.
When the paver grid assembly 100 and head assembly 122 are mounted on the machine, wet concrete product is poured into the cavities in paver grid 110. After wet product is poured into the paver grid, the machine moves head assembly downwardly and the shoes, like shoes 124, compress the product into the paver grid cavities. After sufficient compression, a pallet 126 lowers concurrently with head assembly 122 thus stripping the molded pavers from the grid and leaving them arranged on the pallet as shown in FIG. 1A.
Turning now to FIG. 1B, indicated generally at 128 is a machine for molding concrete blocks and pavers. Included therein are four blocks, like block 130, arranged on pallet 126. In the view of FIG. 1B, the mold that formed blocks 130 has been removed from the machine. Part of the mounting structure for that mold, as well as for paver grid assembly 100, however, is visible. The visible portion of the mounting structure comprises a die support 130. A pair of bolt heads can be seen extending downwardly from die support 131. Before mounting paver grid assembly 100 on machine 128, the bolts are removed and mounting surface 120 (FIG. 1A) is urged against the lower surface of die support 130. Each of the other mounting surfaces on paver grid assembly 100 are urged against corresponding die supports (not visible). The bolts visible in FIG. 1B are thereafter used to bolt each of the mounting surfaces firmly against the underside of the die support thereby securing paver grid assembly on machine 130.
The mold box is vibrated by a pair of opposed vertical vibrating rods 132, 133. Another die support (not visible) is located adjacent rod 133. As can be see in FIG. 1A, a semicircular notch between mounting surfaces 118, 120 is formed to accommodate vibrating rod 132. Vibrating rod 133 is similarly accommodated by corresponding structure (not visible) on mounting bracket 116.
The vibrating rods, like rod 132, vibrate the mold while the shoes, like shoe 124, compact wet concrete product into the cavities. The vibration during compaction increases density, and therefore strength, of the molded concrete product.
Mold boxes are still used because heretofore, molds have been limited to the equivalent of three "16 inch blocks" per mold. The maximum of three "sixteens" per mold has long been recognized as the practical upper limit to the size of a mold which can withstand the high-speed, low-displacement vibration applied to the mold to compact the green concrete once in the mold. In order to increase the "per cycle" throughput of concrete product molding machines, apparatus and methods have been developed in which multiple individual 3--8".times.8""16.times. molds are inserted into a single "mold box", which in turn is mounted on the forming machine as described generally in the references discussed above. While notable advances have been realized in "mold box" technology, the mounting of multiple molds in mold boxes nonetheless represents a significant limitation in the production of formed concrete products.